Which fast lens (35 or 50mm) for D80.

I'm planning to buy a new fast lens which will be used to take pictures of family, my son, people in general (indoor and outdoor) and for occasions where a faster lens is needed (parties, indoor,...). All done with my D80.

I already have the Nikkor AF-S 18-200mm F 3.5-5.6G DX VR.

Which lens would you propose knowing my wife is cutting down my budget (and she knows the internet and the prices (Father's day coming on in Belgium!)

I don't know if I should buy a 35mm or a 50mm... 35 too wide, 50 too narrow for parties and streetphotografie.

I've read on the forum that the Nikkor 1.8 is very good and the 1.4 overpriced and less sharp. Correct?